A preliminary reliability analysis and prediction summary is presented for the radar cross section reduction re-entry vehicle CCS-1FT (REX-3) . The reliability analysis and prediction was performed on the separation and attitude control subsystem as presently defined. The major difference between this second generation vehicle and CS-1FT (REX-1) is that the CCS-1FT (REX-3) vehicle does not not incorporate an Instrumentation Subsystem. Also, the separation and attitude control sub system in...
Topics: DTIC Archive, CHRYSLER CORP DETROIT MI MISSILE DIV, *RADAR REFLECTIONS, *STEALTH TECHNOLOGY,...
The variation in echoing area of a 1/20-scale F-80 aircraft with changing direction of linear polarization has been studied at 9000 mc. For a range of aspects 40 degrees to either side of nose on, in a horizontal plane, power patterns were obtained for polarizations at 0, 15, 30, 45, 60, 75 and 90 degrees inclined to the horizontal. Several patterns of the return from a 1/10- scale F-80 aircraft at 9000 mc have been obtained for ordinary and cross- polarized components of echo. Representative...
Topics: DTIC Archive, OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS ANTENNA LAB, *RADAR REFLECTIONS,...
The SEASAT 1 satellite, which was launched in 1978, carried a radar altimeter which was optimized for operation over the open ocean. However, the instrument did make a significant number of measurements while over land. It is conclusively demonstrated that the radar altimeter serendipitously made measurements over relatively flat terrain which can provide accurate ground elevations. In addition, it is possible that the instrument had some capability to distinguish ground features such as...
Topics: DTIC Archive, Horan,D M, NAVAL RESEARCH LAB WASHINGTON DC, *RADAR REFLECTIONS, *ALTIMETERS,...
Reprint: Storm Time Electric Field Penetration Observed at Mid-Latitude.
Topics: DTIC Archive, Yeh, H -C, HAYSTACK OBSERVATORY WESTFORD MA, *MAGNETOSPHERE, *CONVECTION, IONOSPHERIC...
Topics: DTIC Archive, MYERS, G. F., NAVAL RESEARCH LAB WASHINGTON DC, *REFLECTION, *RADAR REFLECTIONS,...
This final report documents the results obtained through the final phase of the research study. It consists of two papers that have been submitted for publication based on the research. The objective of this project is to quantitatively evaluate the worth of radar-rainfall estimates for physically based hydrologic modeling. These two papers contain valuable results. To summarize, our study has shown that the physical relationship between radar reflectivity and rainfall rate begins to disappear...
Topics: DTIC Archive, Ogden, Fred L, CONNECTICUT UNIV STORRS, *RAINFALL INTENSITY, *RADAR REFLECTIONS,...
The memorandum investigates the steady-state perturbations of the ion and electron densities caused by a large-radius conducting disk moving through the ionosphere at a speed intermediate to the ion and electron thermal speeds. An approximation to the electron density in the region close behind the body is found by solving Poisson's equation, neglecting the ion density. For larger distances behind the body where the ion and electron densities are almost equal, an expression for the Fourier...
Topics: DTIC Archive, RAND CORP SANTA MONICA CA, *IONOSPHERE, *WAKE, ELECTRON DENSITY, IONOSPHERIC...
Studies of the electron-density, electron and ion temperatures in the F-region were made by means of ground-based radar observations at the Millstone Hill Radar Observatory. A 70-meter parabolic antenna directed vertically and a 2.5-Mw pulse radar operating at 440 Mcps were employed for these measurements which were conducted for periods of 30 hours at approximately weekly intervals throughout 1963. Examination of the echo power as a function of height leads to a profile of electron density...
Topics: DTIC Archive, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *ELECTRON DENSITY, *IONOSPHERE,...
The long-range objective of this work is to develop a detailed characterization of non-Bragg scattering from a wind-roughened water surface, or a breaking wave region, and establish a link between radar observations and physical processes, leading ultimately to a more complete, physically-based model for predicting radar scattering from the sea surface.
Topics: DTIC Archive, WASHINGTON UNIV SEATTLE APPLIED PHYSICS LAB, *AIR WATER INTERACTIONS, *OCEAN SURFACE,...
This paper serves to elucidate the mathematical steps needed to apply near-field imaging over a significant (angular) area of regard, with specific application to the receiving sites of the Air Force Space Surveillance System (AFSSS, Space Fence). Cornwell has developed the mathematical formalism to merge near-field imaging with imaging over a wide field of view. The traditional far-field, narrow field-of-view imaging developed in radio astronomy can be extended to wide fields of view by taking...
Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON DC REMOTE SENSING DIV, *RADIO ASTRONOMY, *RADIO...
Project STORMFURY is a joint Department of Commerce (NOAA) - Department of Defense (Navy) program of scientific experiments designed to explore the structure and dynamics of tropical cyclones and their potential for modification. The Project which was formally established in 1962 has as its principal objective experimentation directed towards changing the hurricane's energy exchange by strategic seeding from aircraft with silver iodide crystals. The crystals are dispensed from pyrotechnic...
Topics: DTIC Archive, NATIONAL HURRICANE RESEARCH LAB MIAMI FL, *TROPICAL CYCLONES, WIND, REPORTS, ICE,...
This report treats the theoretical problem of joint estimation of the wake and hard body cross sections (the parameters of the Rice distribution) from either incoherent or coherent radar data.
Topics: DTIC Archive, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *RADAR REFLECTIONS, *STATISTICAL...
An experimental and analytical study of a particular time-domain signature for radar space object identification is described. Measured data presented for several simple metallic shapes which demonstrate the direct relationships between the physical properties of a radar target and its time- domain signature are presented. Valid time-domain signature waveforms obtained by combining three-frequency low resonance scattering data and short pulse radar data are also presented. Finally, a new,...
Topics: DTIC Archive, OHIO STATE UNIV COLUMBUS ELECTROSCIENCE LAB, *RADAR TARGETS, RADAR IMAGES, GEOMETRIC...
Topics: DTIC Archive, VanZandt, T E, ALASKA UNIV FAIRBANKS GEOPHYSICAL INST, *GRAVITY WAVES, *ATMOSPHERIC...
Specular returns from radar targets contain large power which makes a technique based on the analysis of speculars attractive. Herein, the specular returns from a flat region and from a smooth surface tangent to a plane along a curve, which are the largest returns for reasonably sized bodies, are used to obtain information about the geometry of the target.
Topics: DTIC Archive, Lewis, R M, MITRE CORP BEDFORD MA, *RADAR CROSS SECTIONS, GEOMETRY, RADAR...
Standard radar clutter reflectivity models such as the GIT sea clutter model [1,2] and the Billingsley land clutter model [3,4] are based upon many measurements, in part to remove the effects of varying propagation environment, in order to predict radar reflectivity for standard propagation. It has been known for some time that radars on ships operating in regions near land are often subject to clutter amplitudes that vary significantly from these models, and this is due to anomalous...
Topics: DTIC Archive, NAVAL SURFACE WARFARE CENTER DAHLGREN DIV VA, *SHIPBOARD, *RADAR CLUTTER, SEA...
The objective is to determine means for computing the radar cross section of objects in a variety of different environments. This has led to an extension of the investigation to include not only the standard boundary-value problems, but also such topics as the emission and propagation of electromagnetic and acoustic waves, and phenomena connected with ionized media.
Topics: DTIC Archive, Kleinman, R E, MICHIGAN UNIV ANN ARBOR RADIATION LAB, *RADAR REFLECTIONS, SCATTERING,...
The concept of utilizing sound waves as reflectors for pulsed Doppler radar as a means for measuring wind velocity, turbulence, and air temperature has been examined theoretically. Any extension of the initial and successful, small scale experiments performed by Midwest Research Institute to a practical system for atmospheric probing is shown to require a change in the operating concept of the acoustic system. This change involves the abandoning of the concept of coherent reflection...
Topics: DTIC Archive, BOLT BERANEK AND NEWMAN INC CAMBRIDGE MA, *OPERATIONS RESEARCH, *ATMOSPHERIC...
A major objective of this contract is to construct a Quiescent Uniform Ionospheric Plasma Simulator (QUIPS) to be used in analyzing and modeling the results of various field experiments in which a region of the ionosphere was artificially excited by a radar scattering. In this report the general design considerations for the facility are reviewed and a final design and fabrication schedule is presented. The current status of the construction as well as some of the preparations for the...
Topics: DTIC Archive, Arnush, Donald, TRW SYSTEMS GROUP REDONDO BEACH CA, *IONOSPHERE, MICROWAVES, PLASMA...
Site reflections reduce the isolation of omniazimuth antennas below the value required for stable operation of the high-gain amplifiers used in lectronic decoy systems, unless the top of the highest mast is used as an antenna site. An analysis and development program to build a dual semi-circular azimuth coverage antenna has been conducted. The objectives were to choose a universally available site, measure the ships structure reflection from this site, develop an antenna with a pattern shaped...
Topics: DTIC Archive, Jesswein, A J, NAVAL RESEARCH LAB WASHINGTON DC, *SHIP ANTENNAS, INSTALLATION, RADAR...
In support of the SECEDE 2 barium release test series, AVCO-Everett Research lab. conducted an experiment to demonstrate the feasibility of making measurements of spatial density distribution in a barium ion cloud. The feasibility measurements were made with a laser radar breadboard which transmits laser pulses at the wavelengths of the 4934A ion ground state resonance line, and detects the return signals by means of a collecting telescope and photomultiplier, all mounted on an alt-azimuth...
Topics: DTIC Archive, Itzkan, I, AVCO EVERETT RESEARCH LAB INC EVERETT MA, *OPTICAL RADAR, DATA PROCESSING...
The report presents numerical results in the form of graphs of the power reflection coefficient for electromagnetic signals normally incident upon a plasma gradient. An electron collision frequency that is independent of position in the plasma interface is assumed. A 'slide rule' is provided to enable quick determination of the magnitude of the reflection coefficient for 'very overdense, exponential plasmas' in the lower atmosphere (to 70 km) for frequencies from 30 MHz to 10,000 MHz. For...
Topics: DTIC Archive, Chesnut, Walter G, STANFORD RESEARCH INST MENLO PARK CA, *PLASMAS(PHYSICS), *RADAR...
High-frequency scattering by a perfectly conducting N-noded pyramid is investigated. The principally polarized radar cross section is derived by integrating the fields scattered from a wedge around the base termination and, also, the longitudinal edges. The theoretical results are compared with measurements and shown to be in reasonable agreement.
Topics: DTIC Archive, Schoendorf, William H, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *RADAR CROSS...
A high-power hf transmitter was used to illuminate the moon at moonrise. The returned signals which have been observed display both the smooth-sphere scattering components and the rough-scatterer components reported previously by observers utilizing the vhf and uhf bands. It is believed that this study represents the first evidence of similar scattering phenomena observed at high frequencies. During most observation periods, the initial appearance of the moon-reflected signal was later than...
Topics: DTIC Archive, Utley, F H, NAVAL RESEARCH LAB WASHINGTON DC, *RADAR REFLECTIONS, REFLECTION, WAVE...
Topics: DTIC Archive, Aarons, Jules, BOSTON UNIV MA CENTER FOR SPACE PHYSICS, *AURORAE, *IONOSPHERIC...
The effect of surface roughness on the radar backscattering cross section of a perfectly conducting nominally spherical target is examined by applying the Kirchhoff method. It is shown that, for the type of roughness and sphere size to which the Kirchhoff method is applicable, the standard deviation of the cross section increases with frequency according to the law 2 square root of (2 sigma sub 0) K zeta until the first Fresnel zone reduces in size to the scale length of the roughness. At this...
Topics: DTIC Archive, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *RADAR CROSS SECTIONS,...
Research involving the region of clouds in which snowflakes and ice crystals melt is reviewed. Studies of how ice crystals and snowflakes melt are examined and show that in general, melting is slower and less structured than was previously realized. An investigation of the radar bright band is included. The increase of returned signal from the melting particles in the bright band comes from the increase of the index of refraction when the particles turn from snow to water. This is not a...
Topics: DTIC Archive, Cohen,I D, AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA, *MELTING, *RADAR REFLECTIONS,...
Topics: DTIC Archive, RICHARDSON, R. E., MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *BIRDS, *RADAR...
The topic of radar reflectivity of aurora effects is discussed. The report describes a method for representing the volume backscattering characteristics of auroral irregularities. The objective was to develop a universal relationship for calculating the aurora reflectivity. The expression would then normalize all radar-dependent parameters, including geographic location. In attempting to derive a classical solution to the problem, some ambiguous terms remain. However, the technique should prove...
Topics: DTIC Archive, Mitchell,M J, M AND S COMPUTING INC HUNTSVILLE ALA, *RADAR REFLECTIONS, *AURORAE,...
We evaluate how well fractals match the radar backscatter of natural backgrounds in terms of dependence on angle of incidence. We discuss the parameters that define the particular surfaces studied. Finally, we compare the radar backscatter from a range of fractals to experimental backscatter data from natural backgrounds, and we discuss the suitability of fractal surfaces as modeling surrogates for the still more complex natural backgrounds.
Topics: DTIC Archive, Evans, Roger, ARMY TANK-AUTOMOTIVE AND ARMAMENTS COMMAND WARREN MI, *BACKSCATTERING,...
Clear air radar angels were tracked with an FPS-16 radar at Wallops Island, Virginia. Observations were made at different times of the year under a variety of weather conditions. On cloudy days, echoes having characteristics similar to clear air angels were tracked. The radar had a beam width of 1.2 degrees, a wavelength of 5.5 centimeters, and was operated at a pulse length of .25 microsecond with a peak power of 1.2 megawatts. Data consist of flight trajectories of the echoes and a record of...
Topics: DTIC Archive, Roelofs, T H, CORNELL UNIV ITHACA NY, *RADAR METEOROLOGY, *RADAR INTERFERENCE,...
When a circularly polarized wave is incident on a trihedral corner reflector, the backscattered wave is circularly polarized with the opposite sense of rotation. However, by coating one of the conducting surfaces of the reflector with dielectric layers, it is possible to obtain a circularly polarized backscatter wave having the same sense of rotation as the incident wave. With the aid of a digital computer, the thicknesses of the dielectric layers can be optimized in an efficient manner to...
Topics: DTIC Archive, OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS, *COMPUTER PROGRAMMING, *OPTIMIZATION,...
Consider the effect of a field aligned current on the development of plasma instabilities in the auroral electrojet. It is found that the inclusion of the parallel current modifies the threshold criteria for the onset of the Farley Buneman instability, and may cause excitation of oblique ion sound waves. Apply these results to the auroral E region and show that they explain some observations of auroral irregularities, for example, the presence of type I irregularities for sub-threshold...
Topics: DTIC Archive, Chaturvedi,P K, NAVAL RESEARCH LAB WASHINGTON DC, *AURORAE, *ELECTROJETS,...
The purpose of this paper is to discuss some of the geophysical aspects of atmospheric refraction and its effect on radars. Of special concern is the cause-and-effect relationships associated with the trapping of electromagnetic energy into atmospheric duct layers that result in anomalous propagation conditions and extend radar ranges far beyond the normal radar horizon.
Topics: DTIC Archive, Purves, Charles G, NAVAL RESEARCH LAB WASHINGTON DC, *ATMOSPHERIC REFRACTION, *RADAR...
An efficient recursive solution is developed for the transmission and reflection coefficients of a plane multilayer and for the scattering pattern of a cylindrical multilayer. The two principal polarizations are considered, and digital-computer programs are included. The technique is also applicable to the multilayered sphere. The appropriate equations are also given for the reflection coefficients of a perfectly conducting plane which is coated with a stack of homogeneous dielectric sheets,...
Topics: DTIC Archive, OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS, *RECURSIVE FUNCTIONS, COMPUTER...
Raindrop cameras were reinstalled on the East Central Illinois Raingage Network. Results of stratifying drop size data from Majuro with respect to height of the condensation level are presented. These indicate that there are significant difference in the distribution, but the explanation of these differences is not clear. An example of a time sequence of drop size data obtained at Mt. Withington, New Mexico, is presented.
Topics: DTIC Archive, Mueller, E A, ILLINOIS STATE WATER SURVEY DIV URBANA, *RAINDROPS, *RADAR SIGNATURES,...
An earlier theoretical study of radar reflection from a rough planetary surface is extended to include the case where the surface correlation function consists of two or more components. When both large- and small-scale structures are simultaneously present, it is found that the latter may completely dominate the autocorrelation function of the echo and thus render the former undetectable by c-w methods. An additional finding is that the large-scale structure may be detectable in the angular...
Topics: DTIC Archive, Daniels, Fred B, ARMY ELECTRONICS LABS FORT MONMOUTH NJ, *RADAR REFLECTIONS, *MOON,...
Measurements were made to determine the effect of the Reflection Plotter on the visibility of simulated radar signals on PPI screens. Three sizes of target were viewed at 12 inches on a CRT with a P-7 phosphor. These were: small (1 microsec X 1 deg), medium (3 microsec X 10 deg) and large (10 microsec X 30 deg). The data were obtained by the method of attenuating an eight volt signal until a just visible signal was discerned. This measure was expressed in decibels attenuation and was found at...
Topics: DTIC Archive, JOHNS HOPKINS UNIV BALTIMORE MD PSYCHOLOGICAL LAB, *RADAR SIGNALS, *RADAR...
Topics: DTIC Archive, CONLON, J .R., NAVAL RESEARCH LAB WASHINGTON DC, *OCEAN WAVES, *RADAR REFLECTIONS,...
This report provides radar designers with background information on how the idealized free-space radar theory must be modified to take account of reflections from the earth's surface. It is primarily concerned with problems that arise in designing systems that are airborne and contains discussions of the following topics: effects of reflections from the earth on the signal received from an elevated target, implications of these effects for detection and parameter estimation, effects of surface...
Topics: DTIC Archive, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *RADAR INTERFERENCE, PROPAGATION,...
Radio-echo studies of the lunar surface in the wavelength range 3 meters to 10 cm indicate that the surface is smooth and undulating for the most part, with an average surface gradient of the order of one in ten. Photometric studies of the brightness distribution over the moon's disk, on the other hand, demonstrate the existence of microstructure which causes the surface to appear very rough at these much shorter wavelengths. This report describes radio-echo measurements of the reflection...
Topics: DTIC Archive, EVANS, J V, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *MOON, TERRAIN, RADAR...
The contribution of brine layers to observed reflective anisotropy of sea ice at 100 MHz is quantitatively assessed. The sea ice is considered to be a stratified, inhomogeneous, anisotropic dielectric consisting of pure ice containing ordered arrays of conducting inclusions (brine layers). Below the transition zone, the ice is assumed to have constant azimuthal c-axis orientation within the horizontal plane, so that the orientation of brine layers is uniform. The brine layers are also assumed...
Topics: DTIC Archive, Golden,Kenneth M, COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH, *RADAR...
The report is a summary of the Millstone Radar tracking activities during the early revolutions of Echo II. Eight revolutions were tracked and cross-section measurements taken during the satellite's first four days in orbit followed by four additional tracks during the next three weeks. All cross- section measurements beginning with Rev. 4, the first observable at Millstone, display a fading pattern indicating that the balloon had not attained full sphericity, or at least contained significant...
Topics: DTIC Archive, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *ARTIFICIAL SATELLITES, RADAR...
Movement of liquid water through snowpacks is one of the least understood aspects of snow hydrology Richter-Menge and Colbeck 1991. It has an important influence on the timing and magnitude of snowmelt hydrographs Caine 1992 and on biogeochemical and geomorphological processes Williams and Melack. 1989: Caine. 1995. Adapting more physically-based approaches to understand and model flow through a snowpack should permit wider applications of operational snowpack models to more sites and allow for...
Topics: DTIC Archive, Williams, M W, COLORADO UNIV AT BOULDER, *SNOW, WATER FLOW, HYDROLOGY, DIELECTRIC...
The document reports the results of a coordinated program of ionospheric observations pertaining to high-latitude geoacoustics research. The program consisted of two types of measurements, aimed respectively at study of Auroral Infrasonic Waves (AIW's) and Traveling Ionospheric Disturbances (TID's). Understanding these two phenomena is relevant to the problem of detecting and interpreting remote, man-made atmospheric pressure disturbances such as those that result from nuclear detonations.
Topics: DTIC Archive, Fremouw, Edward J, STANFORD RESEARCH INST MENLO PARK CA, *MICROBAROMETRIC WAVES,...
Doppler radar data acquired during the 1981 Joint Agency Turbulence Experiment are presented. Pulse-pair processed reflectivity factor and Doppler spectrum mean data collected during volume scan periods are displayed over constant height surfaces at aircraft penetration level. Time histories of tracking-gate Doppler spectrum mean and variance data collected during aircraft storm penetration periods are also presented. These data show the Doppler spectrum variance to be poorly correlated with...
Topics: DTIC Archive, Bohne,A R, AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA, *TURBULENCE, *RADAR REFLECTIONS,...
A series of sensor-oriented characterization measurements in support of the experiment's remote sensing efforts from the Polarbjorn ice strengthened ship during the 1983 Marginal Ice Zone Experiment were conducted. Measurements describe the physical properties of the ice in this region and are reported herein. Descriptions include: ice and snow thickness; ice salinity profiles; air, ice and snow temperatures; the construction of the snow pack; and general comments about floe topography.
Topics: DTIC Archive, Onstott,R G, KANSAS UNIV/CENTER FOR RESEARCH INC LAWRENCE REMOTE SENSING LAB, *Sea...
The simplified model discussed in this paper is applicable to that portion of the re-entry trajectory where the flow may be considered to be inviscid and laminar. This corresponds roughly to a range of altitudes from 180,000 to 250,000 ft. The viscous effects become important above 250,000 ft and the flow is likely to be turbulent below 180,000 ft. In this range of altitudes the model gives results which agree with the numerical results of Feldman. In computing the electromagnetic...
Topics: DTIC Archive, Engel, R D, RAND CORP SANTA MONICA CA, *ATMOSPHERE ENTRY, *HYPERSONIC VELOCITY,...
Topics: DTIC Archive, KATZIN, MARTIN, ELECTROMAGNETIC RESEARCH CORP COLLEGE PARK MD, *TERRAIN, *RADAR...
Topics: DTIC Archive, Aarons, Jules, BOSTON UNIV MA CENTER FOR SPACE PHYSICS, *IONOSPHERIC DISTURBANCES, *F...